Cardiovascular Simulation, Inc has developed software, cvSim-3DTM, to augment coronary computed tomographic angiography (CCTA) with patient-specific blood flow data and provide a noninvasive alternative to diagnostic cardiac catheterization for assessing the hemodynamic significance of coronary artery lesions. We estimate that, even accounting for the costs of CCTA and cvSim-3DTM, this would save the U.S. health care system at least $6 billion annually and result in better care for patients. Of the patients who get diagnostic cardiac catheterization (the 2nd most common medical procedure) in the U.S. each year, approximately 50% of them do not have hemodynamically significant lesions. Recent clinical data from the DEFER and FAME studies indicate that patients without hemodynamically significant lesions should be treated with medical therapy, not angioplasty and stenting. CCTA has provided an unprecedented ability to noninvasively visualize the coronary arteries and identify patients with coronary artery disease, but is insufficient for determining whether patients with intermediate lesions would benefit from percutaneous coronary interventions (PCI). Fundamentally, CCTA provides exquisite information on coronary anatomy and morphology of disease, but lacks physiologic information on coronary blood flow. We have developed methods to quantify blood flow in patient-specific models of the human coronary arteries and predict the hemodynamic significance of coronary lesions at rest and during physiologic challenge. This approach involves creating a three-dimensional finite element model of the aortic root and coronary arteries from CCTA data, coupling a lumped parameter heart model at the aortic inlet and lumped parameter models at the aortic and coronary outlet boundaries and simulating pulsatile blood flow and pressure using custom computational fluid dynamics methods. We believe that our software, used in conjunction with CCTA, will be able to reliably identify the lesions that are not hemodynamically significant, and therefore dramatically reduce the number of diagnostic cardiac catheterizations that are performed each year. The purpose of Phase I of this SBIR grant is to conduct a pilot clinical correlation study to demonstrate and evaluate our methods for modeling coronary blood flow. PUBLIC HEALTH RELEVANCE: Cardiovascular Simulation, Inc's has developed software, cvSim-3DTM, to simulate coronary blood flow in patient-specific models created from coronary computed tomographic angiography (CCTA) data and predict hemodynamic significance of lesions. This software will be used to model coronary blood flow from CCTA data in 30 patients, and then will be evaluated by comparing predictions for each patient to pressure measurements made during diagnostic cardiac catheterization.